Preliminary study on the Quaternary marine terrace deposits in the southeastern coast of Korea:
Implications in relative sea-level change
Ho Il Lee
*
․In Sung Paik․Hee Cheol Kang․Jung Min Kim
Dept. of Earth Environmental Sciences, Pukyong National University, [email protected]
Marine terraces along the eastern coast of Korean Peninsula have been well known and studied in geomorphological aspects. They are generally related to the interaction between global sea-level changes and tectonical uplift due to opening of the East Sea (Sea of Japan).
In this study terrace deposits at three sites in southern part of the eastern coast in Korea are described in sedimentological and stratigraphical aspects. Terrace deposit at Site 1 is un- derlain by the Miocene Duho Formation of the Pohang Basin with unconformity. It is comprised of sandy mud, conglomerate, planar- to cross-laminated fine- to medium-grained sand and cross-laminated fine- to medium-grained sand in ascending order, which are interpreted to be backshore to upper shoreface deposits. Terrace deposits at Site 2 is composed of sandy mud or silt, planar- to cross-laminated fine- to medium-grained sand, cross-laminated fine- to medium-grained sand and planar- to cross-laminated fine- to medium-grained sand in as- cending order, that is interpreted to be offshore, shoreface to foreshore, backshore and shore- face deposits. Terrace deposits at Site 3 consist of clast-supported conglomerates. They show thickening- and coarsening-upward profile that is interpreted to be storm deposits.
Paleoenvironmental changes at each site can be correlated with MIS based on their relative elevations and absolute age data by previous studies. Site 1 may be correlated with the early MIS 3. Site 2 may be corresponding to the boundary between MIS 4 and MIS 3. Although absolute age of Site 3 deposits is unknown, Site 3 seems to be correlated with the Site 1 based on the elevation. This study can provide the information not only to understand relative sea-lev- el changes but also to interpret tectonic history in East Sea (Sea of Japan) during the Quaternary.
